Pre-travel - Movement of the switch actuator between free and operating position

Over-travel - Movement of the switch actuator beyond the operating position

Total Travel - The sum of pre-travel and over-travel

Insulation Resistance - resistance as measured between the normally closed terminals, or between all terminals connected together and a metal plate to which the switch is mounted. In dry conditions the value would be expected to be greater than 5MΩ.

Switch Resistance - a total resistance offered by a switch in a circuit, as measured from terminal through mating contacts, to terminal.

Transit Time - the time taken by the moving contact in a snap-action mechanism to move from one stable position to another.